I've a 110mm grey plastic soil pipe with a saddle strap glued on that has been fitted below level to connect to a sink basin waste running inside the upstairs first floor. I want to seal the saddle off but don't want to replace the pipe that would involve lots of work. I want to ensure that the hole in the saddle is completely filled upto the inside surface of the 110mm pipe to avoid waste build up and blockage up at that point, any ideas please.